Cooled sheave assembly, particularly for wire enamelling apparatus



P. TOUZE 3,356,133 COOLED SHEAVE ASSEMBLY PARTICULARLY FOR WIRE Dec. 5, 1967 ENAMELIIJING APPARATUS Filed Aug. 2, 1965 V42 ll 93" l IIIIIIII ll INVENTOR: PIERRE 6. 75025 KEIIIFK United States Patent 3,356,133 COOLED SHEAVE ASSEMBLY, PARTICULARLY FOR WIRE ENAMELLING APPARATUS Pierre Touz, Reims, France, assignor to Compagnie l rancaise Thomson-Houston-Hotchkiss Brandt, a corporation of France Filed Aug. 2, 1965, Ser. No. 476,352 7 Claims. (Cl. 165-47) ABSTRACT OF THE DISCLGSURE The sheaves have rims which are spaced closely adjacent but leave a small airgap therebetween, and preferably having an unsymmetrical V cross section with the longer leg overlapping the shorter leg of an adjacent sheave; and an air duct introducing air under differential pressure axially of the sheave assembly to flow past the longer leg of the V, cool the sheave, and escape through the gap.

The present invention relates to a cooled sheave assembly, particularly to guide wire which is passing through an enamelling oven.

When wire is covered with an enamel-type insulating material, it is customary to pass the wire having enamel deposited thereon through an oven in order to speed the drying of the enamel, or the curing of the insulating lacquer, varnish, or synthetic covering.

Pulleys, or sheaves, guiding such wire coming from, or arranged in or close by to the enamelling towers and furnaces need cooling. It has been found, for example, that in a group of eight adjacent sheaves to guide the wire, having aluminum rims about one foot diameter, a temperature of 130 C. has been measured at the surface of the rim under ordinary operating conditions. When the temperature at the sheave reaches a point which interferes with proper functioning of the sheave assembly, or the enamelling process of the wire, artificial cooling must be resorted to. It has been proposed to provide an air blast directed against the rims from the outside thereof, essentially in a radial direction. The difiiculty with such an arrangement is that the air blast impinges on the rims and, being deflected thereby, does not reach the axles or bearings at the center of the sheaves which need cooling the most. A portion of the cooling air thus is not effectively used. Further, since the rims of the sheaves are usually comparatively thin, transfer of cooling effectiveness from the rims to the webs or spokes of the sheaves, and then to the bearings is not effective.

It is an object of the present invention to provide a sheave assembly permitting efficient utilization of a cooling fiuid such as air, and cooling the center, that is the sheave bearings as well as the rim thereof.

Briefly, the present invention provides a sheave assembly mounted on an axle in which a plurality of individual pulleys, or sheaves are mounted adjacent to each other. The sheaves have rims, known in prior art, which are arranged close to each other. The rims are supported from the hubs of the sheaves by spokes, or by apertured webs. A fluid flow, for example, an air blast, is directed towards the center of the sheaves. Communication is effected between the spokes, or through the apertures of the webs; the air can escape through the space between the rims.

Two air blasts may be directed from either side of the sheave assembly; or the last one of the sheaves may have a solid web and air is blown in axially from one side only. The solid web deflects the air through the space past the rims of the sheaves. The rims of the ice sheaves preferably are arranged to have a V groove (seen in cross-section). This V is preferably unsymmetrical With respect to its apex, and formed to have a pair of legs, one longer and one shorter. Adjacent pulleys are arranged in such a way that the longer leg overlaps an adjacent shorter one. Thus, the air is directed along the longer leg, and permitted to escape in a gap between the bottom surface of the longer leg and the shorter leg of an adjacent pulley. Air How may be caused either by supplying compressed air, or providing for suction.

The structure, organization and operation of the invention will now be described more specifically in the following detailed description with reference to the accom' panying drawings, in which:

FIGURE 1 is a schematic cross-section of an air cooled sheave assembly, with air supply from either side of the assembly; and

FIGURE 2 is a schematic cross-sectional view similar to FIGURE 1 with air supply at one end only.

Referring now to the drawings, and more particularly to FIGURE 1:

Pulleys, or sheaves 1, are stacked on a shaft, or axle 2. Six sheaves are shown, but any number necessary for the wire enamelling process may be used. Pulleys 1 have hubs 3, rotatively mounted on axle or shaft 2. The axle itself is mounted in vertical supports 4.

The sheaves are actually stacked, one next to the other, in such a manner that between the sheaves a cylindrical space is formed, defined at its ends by the wheel discs, or spokes 6, and at the circumference by the rims of the pulleys 1. If the pulleys 1 are formed with webs, then apertures 5 are provided within the webs in order to provide for series communication between the pulleys. Air guides 7 are provided at either end of the assembly, and shaped to provide guide ducts closely adjacent to the rims of the pulleys.

The rims of the sheaves are formed to have a crosssection of an inverted V. Preferably V is non-symmetrical as seen best in FIGURE 1, and is formed with a short leg 8, and a long leg 9. The pulleys are arranged next to each other in such a manner that the long leg 9 of any pulley overlaps the short leg 8 of an adjacent one. This arrangement provides for good heat exchange between air flow from ducts '"l, as shown by the arrows in the figures.

FIGURE 1 shows a pair of air ducts 7, arranged at either end of the assembly, and directing air towards the center; the air itself escapes in the gap between legs 8 and 9 of adjacent sheaves.

FIGURE 2 shows an arrangement similar to FIGURE 1, where only a single air duct is present, however. The difference in the arrangement from FIGURE 1 is that the last pulley, at the side away from the air duct 7, has a solid Web or disc lit in order to block escape of air axially and to deflect the air radially along the inside of the rims and past the gaps between adjacent rims as shown by the arrows in the drawing.

The air may be supplied under positive pressure, that is by supplying compressed air to ducts 7. If suction is applied at ducts 7, the sense of air fiow as shown by the arrows will be reversed, but the cooling and the other structure remains unchanged. In order to provide for a rapid flow of gas near the rims, the gap between the legs of adjacent pulleys, that is, the gap between legs 8 and 9, should be small in comparison with the lateral width of the rims themselves.

The invention has been illustrated in connection with cooled sheaves for wire towers or enamelling furnaces, but is equally applicable wherever a sheave assembly is desired to be cooled efiiciently.

What is claimed is:

1. Sheave assembly arranged for cooling by a cooling fluid comprising a mounting axle, a plurality of sheaves mounted adjacent to each other on said axle, said sheaves having rims and being mounted to have said rims closely adjacent to each other leaving a space between the rims of adjacent sheaves small in comparison with the widths of the rims; and air duct means introducing cooling air axially of said sheaves at a diiferential pressure with respect to ambient air, said air passing interiorally of said assembly, past said rims, and radially passing said small spaces between adjacent rims.

2. Sheave assembly as claimed in claim 1 wherein, in cross-section, said rims are formed with a V groove, said V groove being non-symmetrical with respect to its apex and forming a longer and a shorter leg; and wherein the longer leg of the V of a sheave overlaps the shorter leg of the V of an adjacent sheave.

Sheave assembly as claimed in claim 1 wherein the air pressure in said air duct means is greater than ambient air pressure.

4. Sheave assembly as claimed in claim 1 wherein the air pressure in said air duct means is less than ambient air pressure.

5. Sheave assembly as claimed in claim 1 wherein a pair of air ducts are provided, one each communicating with the space beneath said rims at each axial end of the assembly.

6. Sheave assembly as claimed in claim 1 wherein beneath said rim at one axial end of the assembly; and a sheave remote from said one axial end is formed with a solid web to prevent axial air flow therebeyond and direct air flow passing said rims and through the space between said rims.

7. In a wire guide sheave assembly for use in wire enamelling ovens wherein said sheaves are air cooled, the improvement comprising forming said sheaves with closely adjacent rims leaving a gap therebetween small in comparison to the width of said rims, said rims having an unsymmetrical V cross section having a longer leg and a shorter leg, adjacent sheaves having the longer leg overlapping the shorter leg, with said gap beneath said longer and said shorter legs and forming said sheaves having apertured webs supporting said rims; and air duct means introducing air under differential pressure axially in the region of said webs whereby air flow in the space below the rims and passing the longer leg of said V of the rims and through the gaps therebetween will cool the sheaves of said assembly.

References Cited UNITED STATES PATENTS 1,400,671 12/1921 Fischer 74-230.6 2,024,743 12/1935 Penney 165186 2,282,633 5/1942 Young 308208 ROBERT A. OLEARY, Primary Examiner.

an air duct is provided communicating with the space CHARLES SUKALO, Examine!- 

1. SHEAVE ASSEMBLY ARRANGED FOR COOLING BY A COOLING FLUID COMPRISING A MOUNTING AXLE, A PLURALITY OF SHEAVES MOUNTED ADJACENT TO EACH OTHER ON SAID AXLE, SAID SHEAVES HAVING RIMS AND BEING MOUNTED TO HAVE SAID RIMS CLOSELY ADJACENT TO EACH OTHER LEAVING A SPACE BETWEEN THE RIMS OF ADJACENT SHEAVES SMALL IN COMPARISON WITH THE WIDTHS OF THE RIMS; AND AIR DUCT MEANS INTRODUCING COOLING AIR AXIALLY OF SAID SHEAVES AT A DIFFERENTIAL PRESSURE WITH RESPECT TO AMBIENT AIR, SAID AIR PASSING INTERIORALLY OF SAID ASSEMBLY, PAST SAID RIMS, AND RADIALLY PASSING SAID SMALL SPACES BETWEEN ADJACENT RIMS. 